Free mandrel, system, protected casing

ABSTRACT

The Invention is to be applied for selective injection of fluids in different formations, keeping the casing isolated from fluid pressure. “Fluid” is used in its widest sense: gases or liquids. It is hydraulically driven by the injection fluid. A single operator must only handle surface standard valves. It consists of five assemblies: Surface, Transport, Free Mandrel, Fixed Bottom Hole and Complementary. The Free Mandrel is the dynamic main device that carries all the Injection valves together, one for each formation, from the Bottom Hole to the Surface in 30′ and viceversa. As this operation is performed many times in the well lifetime, it allows a cumulative time and money saving. Workover equipment is only used for installing the system and for fixing packers. Formation Pressure is kept when the system is installed or when it is pulled up. Changes can be made at any time when they are needed.

This invention is related to elements employed in the petroleum industryin general, but it particularly refers to a free mandrel system withprotected casing. Its main specific purpose is to be applied topetroleum exploitation for the selective injection of fluids indifferent formations of a specific well.

SUMMARY OF THE INVENTION

According to the characteristics of the invention, its main purpose isto achieve a free mandrel system which enables the setting up andsimultaneous lifting of all Injection Valves from the surface byoperating the valves of a surface component of the invention. Thisprocess is performed by only one operator without any kind of help,assistance or tool.

More precisely, this invention has as its main goal the embodiment of afree mandrel system with protected casing created to allow selectiveinjection in several well formations. Consequently, the free mandrelassembly has as many Injection Valves as formations a specific well mayhave. In the present explanation for the embodiment of the invention,the system is applied to a 139.5 mm (5″½) casing and it has beensimplified to only two formations, an upper and a lower one, tofacilitate the explanation and comprehension of its constructive layoutstructure.

Said system is based on a dynamic main assembly, a Free Mandrel, throughwhich Injection Valves are transported from the surface to theirlocation on the bottom hole by means of injection fluid and an orderedsurface valve handling. To this purpose, the Fixed Bottom Hole Assemblyonly allows fluid circulation from the annular to Tubing (9) in order tomake the free mandrel return to the surface where all valves are placed,and remove them. Consequently, the purpose of the invention is achievedby an essential layout which comprises:

(A) A Surface Assembly (SA) made up of an installation Mast, aLubricator with a Catcher to release and catch the Free MandrelAssembly, Conventional Valves and the Impeller which enables it tooperate.(B) A Transport Assembly (TA) made up of a Fishing Neck which contains aRetention Valve, two Rubber Cups which slide over a central tube and aLower Connector which allows it to be bound to the next assembly.(C) The Free Mandrel Assembly (FMA), which is the dynamic element of thedevice, is made up of a mandrel for every formation to be selectivelyinjected (only two in this simplified case), where each mandrel lodgesits corresponding Injection Valve.(D) A Fixed Bottom Hole Assembly (FBHA), which is the device that isscrewed to the bottom of the 73.026 mm (2″⅞) tubing string and over theOn Off. When the Free Mandrel Assembly is inserted into the Fixed BottomHole Assembly, the FMA complements the hydraulic circuits they bothcontain to accomplish selective injection in every formation.(E) A Complementary Assembly (CA), which is screwed to the lower part ofthe Fixed Bottom Hole Assembly (D) and comprises, in its interior part,the Telescopic Union screwed to the central and lower part of the FixedBottom Hole Assembly (D); the Injector Tube; the Injector Plug and theRupture Disc passage.In its exterior part, the Complementary Assembly (E) is made up of theupper part of the On Off screwed to the outer and lower part of theFixed Bottom Hole Assembly (D). The lower part of the On Off is screwedto the upper end of the Upper Packer while the Injector Plug is screwedat its lower end with the Rupture Disk passage. To complete theinstallation, the 60.325 mm (2″⅜) tubing string is screwed to the lowerpart of the Injector Plug to fix the Lower Packer in the adequateposition to separate both formations.

One or two 60.325 mm (2″⅜) tubings are placed below the Lower Packer,and the Shear Out is placed on its end.

Some of the elements described in the above three paragraphs arecommonly used in the industry, but they are essential for the operationof this invention.

Said Free Mandrel (C) runs together with all well valves from theLubricator to its insertion in the FBHA, employing the Catcher of theLubricator to remove or replace the Injection Valves during the upstrokeor removal. For that purpose, its valve system is designed to allowfluid passage from the Annular to the tubing string, blocking thepassage of the fluid from the tubing string to the Annular with thepurpose of protecting the Casing even when this Free Mandrel is notinserted into the FBHA. In other words, it will keep the Casing totallyisolated from the pressure and the contact of the injection fluid. Thisalso facilitates protective fluid circulation (fresh water withgermicide) in the Annular to fill it or use it during the upstroke ofthe Transport (B) and Free Mandrel (C) Assemblies.

Each of these elements has its special own characteristics to achievethe purpose of the invention.

BACKGROUND INFORMATION

In the search for background information, several embodiments have beenfound. Some of the documents are transcribed below:

US2004238218 (A1): Injecting a Fluid into a Borehole Ahead of the Bit,applied by Runia Douwe Johannes, Smith David George Livesey, WorrallRobert Nicholkas; Shell Oil Company.

It describes a method and system for introducing a fluid into aborehole, in which there is arranged a tubular drill string including adrill bit, wherein the drill bit is provided with a passageway betweenthe interior of the drill string and the borehole, and with a removableclosure element for selectively closing the passageway in a closingposition, and wherein there is further provided a fluid injection toolcomprising a tool inlet and a tool outlet, the method comprising passingthe fluid injection tool outlet through the drill string to the closureelement, and using it to remove the closure element from the closingposition; passing the fluid injection tool outlet through thepassageway, and introducing the fluid into the borehole from theinterior of the drill string through fluid injection tool into theborehole.

It does not collide with the purpose of the present description.

US2005011678 (A1): Method and Device for Injecting a Fluid into aFormation. Applicant: Akinlade Monsuru Olratunji (NL), Lightelm DirkJacob (NL), Zisling Djurre Hans, Shell Oil company.

A method of injecting a stream of treatment fluid into an earthformation in the course of drilling a borehole into the earth formation,using an assembly comprising a drill string provided with at least onesealing means arranged to selectively isolate a selected part of theborehole from the remainder of the borehole, the drill string furtherbeing provided with a fluid passage for the stream of treatment fluidinto the selected part of the borehole. The method involves: operatingthe drill string and stopping the drilling operation when a zone forwhich treatment is desired is arranged adjacent to the part of theselected part of the borehole; isolating the selected part of theborehole using the sealing means so as to seal the drill string relativeto the borehole wall; and, pumping the stream of treatment fluid via thefluid passage into the selected part of the borehole and, from there,into the treatment zone.

The mentioned characteristics that identify this embodiment do not giverise to a concrete antecedent of this invention.

U.S. Pat. No. 4,050,516 (A): Method of Injecting Fluids into UndergroundFormations. Applicant: Dresser Ind.

A method of injecting fluids into underground formations such as oilwells, and particularly advantageous for treating low-pressureformations having bottomhole pressures below normal tubing hydrostaticpressure, utilizes the steps of lowering into the borehole a tubingstring, locating near the formation to be treated a partiallypressure-balanced valve adapted to support a column of fluid in thestring of tubing, and applying pressure to the column of fluid in thetubing to inject fluid through the valve into the formation.

It does not interfere with the invention either.

U.S. Pat. No. 4,433,728 (A): Process for selectively reducing the fluidinjection or production rate of a well. Applied by Marathon Oil Co (US).

This process improves the real conformance of fluids injected into orproduced from a subterranean formation via a multi-well system whereinsignificantly greater amounts of fluid than desired are injected into orproduced at least by one well of the multi-well system, in relation toother wells of the system. An aqueous caustic solution and an aqueoussolution containing a polyvalent cation dissolved therein are caused tomix near the well bore environment of said one well, thereby forming aninsoluble precipitate which reduces the permeability of the well boreenvironment substantially over the entire well bore interval. It hasdifferent characteristics that move it away from the embodiment beingcompared.

U.S. Pat. No. 4,433,729 (A): Process for selectively reducing the fluidinjection rate or production. Applicant: Marathon Oil Co (US).

This patent is similar to the previous one. It utilizes apermeability-reducing chemical compound.

CA2086594 (A1): Selective Placement of a permeability-reducing materialto inhibit fluid communication between a near wellbore interval and anunderlying aquifer. Applicant: Marathon Oil Co. (US).

It's also based on injection of a permeability-reducing material.

FR 2855552 (A1): A hydraulic fracturing method for operating e.g. oilwells, includes sequential, pressure-controlled phases of fluid, andballast injection with pause for relaxation or formation. Applicant:Despax Damien (Fr).

The method complies nine successive phases. Fracturing fluid loaded withballast, ballast-free fluid, ballast mixed with fibers or coatedadherents is used in the different phases.

It is clearly shown that there is no interference with this invention.

GB1179427 (A): Equipment for Injecting Fluids into an UndergroundFormation. Applied by Shell Int. research (NL).

Fluid injected into a well is directed into one or two formations ofdifferent resistances to injection and separated by impermeableformation The “soak process” of oil Transport is carried out in a well.Steam injected into the well through a tubing is used to make oil flowinto the tubing. Packers and labyrinth seals are alternatively used.

These characteristics do not appear in this invention.

RU2002126207 (A): Oil Well. Method for Oil Extraction from the Well andMethod for Controllable Fluid Injection into Formation through the Well.Inventors: Stedzhemejer D. L., Vajngar K. D., Bernett R. R., Sevendzh V.M., Karl F. G. M, Khersh D. M.

Well has casing pipe with a plurality of perforated sections andproduction string located inside the casing pipe. An alternating currentsource electrically linked with at least one of casing pipe andproduction string is located on ground surface and serves to conductalternating current from ground surface into well. Controlled wellsection is also provided and it includes communication and control unitelectrically linked with at least one of casing pipe and productionstring, having sensing means and electrically operated valves connectedthereto. Communication and control unit is adapted to regulate flowbetween outer and inner production string parts.

It is unnecessary to go on describing in detail this patent structure asit evidently does not collide with the object of this invention.

U.S. Pat. No. 4,462,465 (A): Controlling injection fluids into wells.Applicant: Otis Eng. Co. (US).

In this patent, a Side Pocket Fix Mandrel is described. It consists of aconstructive variable of mandrels fixed to the bottom of conventionalwells.

In fact, the device is parallel with the main bore. A lateral side portcommunicates the receptacle with the exterior of the side pocket of themandrel. A flow control assembly includes a sliding sleeve valve and acontrol valve, both designed to be removed from the receptacle. Thesleeve valve is movable within the receptacle between a closed positionand an open position relative to the side port, and includes colletfingers having outwardly projecting latching lugs for engagement in areceptacle latching recess in the closed position. The bore of thereceptacle is slightly larger below the latching recess than it is abovethe recess, so that limited inward movement of the latching lugs,restrained by an insert within the sleeve valve, will permit movement ofthe valve downward to the open position but will not allow movement ofthe valve upward from the closed position, so long as the insert is inplace. A control valve, to be selectively placed within the receptacleand latched with the sleeve valve includes a nose which is receivedwithin the sleeve valve and limits the inward deflection of the colletfinger latching lugs. The control valve includes a latching lug forlatching in another receptacle latching recess, when the sleeve valvehas been moved to the lower open position. The control valve and sleevevalve have a coating latching mechanism so that when control valve iswithdrawn, it lifts the sleeve valve to the closed position and thendisengages from the sleeve valve. The sleeve valve includes an internallatching recess to enable withdrawal of the sleeve valve from thereceptacle by a suitable pulling tool.

To conclude, U.S. Pat. No. 4,671,352 (A): Apparatus for selectivelyinjecting treating fluids into earth formations. Applicant: ArlingtonAutomatics Inc. (US).

The formation-treating apparatus described herein, is adapted to bedependently supported in a well bore from a pipe string and whichincludes upper and lower telescoped body members adapted to beselectively moved between upper and lower operating positions forcontrolling the injection of treating fluids into one or more earthformations traversed by the well bore. A pair of spaced packer elementsare mounted on the lower member above and below a discharge port andcooperatively arranged for isolating a well bore interval that is to betreated by discharging one or more treating fluids in the pipe stringfrom the port. To control the injection of treating fluids, retrievablevalve means are also cooperatively arranged within the body members andadapted to be alternatively seated on upper and lower full-bore valveseats in the upper and lower bodies in response to movement of thebodies to their operating positions. In this manner, whenever the upperbody member is moved to one of its operating positions, the valve meanswill be seated on the lower valve seated n the lower valve seat andunseated from the upper valve seat to open fluid communication betweenthe pipe string and the treating tool. On the other hand, whenever theupper body member is moved to its other operating position, the valvemeans will be seated on the upper valve seat to trap treating fluids inthe pipe string and discharge any unused fluids into the well bore.

According to the background information found, it is evident that inknown conventional pieces of equipment, to which the analyzed variablesrefer, all of them use fixed installations in the bottom hole.Consequently, when it is necessary to repair or replace any of thevalves placed inside the mandrel, they have to be brought up to thesurface.

This necessarily demands the presence of specialized equipment at thewell site to raise the mandrel by means of a cable or wire, and a jarsocket or also other pieces of equipment used in the industry.

In order to perform this operation, production has to be stopped, thedevice has to be raised from the bottom hole, necessary replacements aremade, it has to be lowered and then, production is resumed. Thisproduces costs in personnel, down time (during which the well is notoperating) and lead time (between order and delivery of the equipment)at the oil field.

This is the procedure for the maintenance of mechanical systems forconventional fixed installations.

With this invention, all these problems are advantageously solvedbecause the complete mandrel installation is raised. The mandrel is notfixed to the bottom hole because it is free. This results in animportant time and extra hand work advantage because it can be operatedby only one person from the surface by simply handling the valve setprovided by the invention.

To summarize, among other advantages of the invention described herein,the following can be mentioned:

1. Operational Advantage:

Fluid injection is continuous and it is not interrupted in any of theoperational stages as the formations are kept constantly pressurized.That is to say, the fundamental purpose of fluid injection (secondaryrecovery) is to pressurize the formations to achieve a larger formationvolume in the surrounding or adjacent producing wells.

2. Economic Advantages:

Minor investment or cost in initial equipment.

No additional equipment is required, as wireline or slikeline orexternal personnel because valve setting up or removal, and alloperations to fix both assemblies are performed in a significantlyshorter time. This results in reduced time for equipment use.

The operation is performed by control personnel of injector wells(either the operator or field supervisor) from the surface by handlingthe well head manifold valves. The change is immediately performed themoment it is required.

Consequently, for example, for 2500 m deep installations, the FMAdescribed herein, reaches the surface with all valves installed in about30 minutes and requires a slightly shorter time in the downstroke. Bothstrokes are attained with the same injection fluid. This process will beindicated in the operational relation by means of the attached figures.

This also implies that the installations are active during lead time andthe time employed by the equipment to pull up every valve from thebottom hole and replace it for another. This operation is performedafter the well is depressurized. This advantage is utilized severaltimes while the well is producing, thus, accumulatively, adding asignificant value. —It is worth noting that while the equipment isexpected to reach the location and while the operation is beingperformed, the formation pressure is lost and so is its influence on theproducing wells.

A blind plug (not shown in Figures) is provided so that the tubingtightness may be verified at the initial, intermediate and final stageof the installation.

Strokes can be performed to verify the accumulated depositions and inincreasing periods, that is to say, beginning with short periods andincreasing them in order to define the most suitable one for each wellwithout depressurizing the formations, and with no additional equipmentcosts or external personnel.

The inhibited fluid lodged in the Annular can be changed for maximumCasing protection in case of long injection periods without replacinginjection valves or employing pulling equipment to disconnect the On Off(43).

Besides, it can block any formation, examine or stimulate others. Thisis achieved by removing the FMA (C), leaving the formation circuit inservice and blocking the other one. This also allows determining ifthere is any interference between any of the formations by injectingfluid in one and placing Amerada® Gauge, an instrument to measurepressure in the bottom hole, inside another mandrel to verify pressurevariation in different injection flows.

In order to make this invention, a free mandrel with protected casing,more comprehensible so that it can be put into practise easily, adetailed description of a preferable embodiment will be given in thefollowing paragraphs.

This will refer to the accompanying illustrative figures as ademonstrative example but not limiting the invention. Its componentswill be able to be selected among diverse equivalents without movingaway from the invention principles as established in these documents.

BRIEF DESCRIPTION OF THE DRAWINGS

The main invention components are schematically represented in differentviews in the Figures which accompany the present technical and legaldescription. As the component parts have a great length but a relativelysmall diameter, the Figures have been deliberately deformed so that thecomponent parts can be distinguished to be explained. In some of theFigures hydraulic flow circulations, which are necessary for itsoperation, are identified with different conventional symbols:

+=Injection fluid, provided by the Power Plant with the highest pressureflowing into all injection valves to be regulated according to theconditions of every formation.#=Controlled fluid to be injected in the upper formation. It comes outthrough the lower end of the upper valve.*=Controlled fluid to be injected in the lower formation. It comesthrough the lower end of the lower valve.x=Fluid injected at low pressure through the Annular (e1) to achieve thereturn of the Free Mandrel Assembly.

The pressure is approximately 2 to 3 kg/cm². (Obviously the higher thepressure, the faster the return speed, but the mentioned pressure is therecommended one). Again, 30 minute return time is achieved in a 2500 mdeep installation.

--=Fluid removed from the tubing as the Free Mandrel assembly moves upto the surface. Its pressure is slightly lower than the one that pushesup the Free Mandrel Assembly.

=White/empty space=Settled fluid or only with hydrostatic pressure (forexample, in the annular between the casing and the tubing during theinjection process).

As an operative example of the invention, the simplest embodimentapplied to purge water injection of only two formations: an upper and alower one will be described hereinafter, as informed above.

In this description, the Fluid concept will be taken in its widestsense, that is to say, referring to any type of liquid or gas.

The invention equipment is essentially made up of the followingoperative assemblies.

A—Surface Assembly (SA) B—Transport Assembly (TA) C—Free MandrelAssembly (FMA) D—Fixed Bottom Hole Assembly (FBHA) E—ComplementaryAssembly (CA)

The Figures are as follows:

FIG. 1 is an elevational longitudinal sectional view of the generallayout of the invention. Here the position of a series of crosssections, numbers I to VIII, is shown to facilitate the functionalexplanation of the device.

FIG. 2 is an enlarged partial view of one section of FIG. 1 where theSurface Assembly (A), component of the invention, is shown in detail.

FIG. 3 is a detailed view of the Transport Assembly (B), component ofthe invention. When operating, the only fluid that circulates (+) is theone that comes in through 73.025 mm (2″⅞) tubing (9) (i), goes throughthe Fishing Neck (11) and connects with the Upper Free Mandrel (C).

FIG. 4 is an elevational sectional view where the characteristics of theFree Mandrel Assembly (C) and fluid circulation are shown.

FIG. 5 shows both Transport (B) and Free Mandrel Assembly (C) as theyrun through the well from the Lubricator (3) to the Fixed Bottom HoleAssembly (D) in their downstroke, and from the Fixed Bottom HoleAssembly (D) to the Lubricator (3), in their upstroke. Different fluidsare shown inside both assemblies, the incoming one (+), the one to beinjected (#) in the upper formation and the one to be injected (*) inthe lower formation.

FIG. 6 is an elevational sectional view of the Fixed Bottom HoleAssembly (D) with its essential components.

FIG. 7A represents the Fixed Bottom Hole Assembly (D) in connection withthe Free Mandrel (C) and Transport (B) Assemblies. The (+) fluidentering through the 73.025 mm (2″⅞) Tubing (9), the Upper Free Mandrel,the outcoming (#) fluid through the Middle Plug (17) radial passage(19), to be injected in the Upper Formation, in the plane of said MiddlePlug radial passage (19).

FIGS. 7B and 7A are the same Figures but, in 7B, the sectional plane isperpendicular to passage (19). The incoming fluid (+) path is shown.This reaches the lower valve through the middle plug (17) longitudinalpassages (C1) to be injected in the lower formation (*).

FIG. 8 shows the Fixed Bottom Hole Assembly (D) screwed to theComplementary Assembly (E). The Transport Assembly (B) is insertedinside it with the Free Mandrel Assembly (C) during simultaneousinjection in both formations. Fluids are also shown as they circulatethrough different passages.

FIG. 9 only shows the injection in the upper formation (#) of theinvention layout. The Transport (B), Free Mandrel (C), Fixed Bottom Hole(D) and Complementary Assemblies (E) are represented while showingoperative hydraulic paths.

FIG. 10, a transverse sectional view on line III-III (FIG. 1), shows theUpper Formation injection fluid in the Middle Plug (17) axial passageplane (19), the Fixed Bottom Hole Assembly (D), vertical passages (C1)(+) and (C2) (#) and Casing (10). The Annulars (e2) (white space) and(e6) (#) are also shown.

FIG. 11 shows the injection in the Lower Formation (*) of the inventionlayout. In this Figure, The Transport (B), Free Mandrel (C), FixedBottom Hole (D) and Complementary (E) Assemblies are represented whileshowing operative hydraulic paths.

FIG. 12, a transverse cross-sectional view on line IV-IV (FIG. 1), showslower formation (*) fluids flowing out of the Lower Injection Valve (21)and fluids involved in lower formation injection. As in the previousFigure the Casing (10), the Fixed Bottom Hole Assembly (D) and the LowerPlug (22) are also shown together with (C2) (white space) and (C3)(white space) passages, and the Annular (e2) (white space).

FIG. 13 shows simultaneous injection in both formations. The incomingplant fluid (+) is controlled by the corresponding valves for Upper (#)and Lower (*) Formation injection.

The Transport (B), Free Mandrel (C), Fixed Bottom Hole and (D) andComplementary Assemblies (E) are represented while showing operativehydraulic paths with the above mentioned symbols (+, #, *).

FIG. 14, a transverse cross-sectional view on line V-V (FIG. 1),corresponds to Upper and Lower Formation simultaneous injection at theheight of the Casing Protective Valve (36) of the Fixed Bottom HoleAssembly (D) lower end. Upper Formation injection fluid (#) goes throughthe Annular (e9) defined by the FBHA (D), inner diameter and the outerdiameter of the inner body of the Telescopic Union (37) and the (*)fluid through the inside of the Telescopic Union (37).

FIG. 15, a transverse cross-sectional view on line VI-VI (FIG. 1),corresponds to the lower part of the Fixed Bottom Hole Assembly (D)below the Casing Protective Valve (36) with the simultaneous injectionfluids (e9) acting in the Upper (#) and Lower Formations (*) through theinside of the Injection Tube (40).

FIG. 16, a transverse cross-sectional view on line VII-VII (FIG. 1),shows Upper and Lower Formation fluid injection, and fluid circulationin the Injector Plug (41) plane through the Rupture Disc passage (42).Casing Upper Perforations (49), Injection Tube (40) and the InjectorPlug (41) together with Annulars (e3) (#) and (e11) (#) can also beseen. Lower Formation fluid (*) circulates through the inside of theInjection Tube (40).

FIG. 17, a transverse cross-sectional view on line VIII-VIII (FIG. 1),only shows Lower Formation injection (*) and fluid circulation in theShear Out (48) passage plane and Casing Lower Perforations (50) in thatarea. Annular (e5) (*) and the Shear Out inner passage (*) (C4) are alsoshown.

FIG. 18 represents fluid distribution during the Free Mandrel Assembly(C) upstroke and when the System injects in both formations without flowcontrol and with low pressure (x). It is only when the Free MandrelAssembly (C) hooked in the Transport Assembly (B) is inserted in itsposition inside the Fixed Bottom Hole Assembly (D) that the injection inboth formations is controlled.

The resulting hydraulic circuits can be identified with the symbols thatrepresent the operating pressures. In the Annular (e1) (x) and in the73.026 mm (2″⅞) tubing (9) (i) (--).

FIG. 19 shows a transverse cross-sectional view on line I-I (FIG. 1)with fluid circulation in simultaneous injection process in bothformations. This takes place at the Well Head (8). The Casing (10) andthe 73.026 mm (2″⅞) Tubing (9) (i) are shown. There is only hydrostaticpressure (white space) in the annular between them (e1). There is (+) inthe inside of the Tubing (9).

FIG. 20, a transverse cross-sectional view on line II-II (FIG. 1), showsfluid circulation in the Free Mandrel Assembly upstroke, (--) flowinginside the 73.026 mm (2″⅞) Tubing (9) (i), and (x) through (e1).

DESCRIPTION OF THE INVENTION COMPONENTS

FIGS. 1-20 above, specially developed for this description, will betaken as reference. In these Figures, the main details of all the partsof the essential assemblies that make up the invention have been takeninto account.

These parts are the following:

-   1—Pipeline from Water Power Plant-   2—Catcher-   3—Lubricator-   4—Mast-   5—Impeller-   6 ₁—V1 (Standard Valve)-   6 ₂—V2 (Standard Valve)-   6 ₃—V3 (Standard Valve)-   6 ₄—V4 (Standard Valve)-   6 ₅—73.026 mm (2″⅞) conventional full passage Injection Valve-   7—Retention Valve-   8—Well Head-   9—73.026 mm (2″⅞) Tubing-   i—Tubing (9) Interior (Direct)-   e1—Annular between 9 and 10-   10—Casing-   11—Fishing Neck-   12—Retention Valve-   13—Rubber Cups-   14—Lower Connector-   15—Outer Jacket-   16—Seal Ring-   17—Middle Plug-   18—Upper Formation Injection Valve-   19—Middle Plug radial passage-   20—Seal Ring-   21—Lower Formation Injection Valve-   22—Lower Plug-   23—Seal Ring-   24—Upper Body-   25—Upper Packer Collar-   26—Seal Ring-   27—Lock Nut-   28—Lower Body-   29—Seal Ring-   30—Spacer-   31—Spacer Injection outlet Perforation-   32—Lower Packer Collar-   33—Seal Ring-   34—Seat-   35—Seal Ring-   36—Casing Protective Valve-   37—Telescopic Union inner body-   38—Seal Ring-   39—Telescopic Union outer body-   40—Injection Tube-   41—Injector Plug-   42—Rupture Disc passage-   43—On Off-   44—Upper Packer-   46—Lower Packer-   47—60.325 mm (2″⅜) Tubing-   48—Shear Out-   49—Casing Upper Perforations—Upper Formation-   50—Casing Lower Perforations—Lower Formation

In FIGS. 10, 12, 14, 15, 16, 17, 19 and 20, which correspond todifferent transverse cross sectional views of the Casing, there arevertical passages and Annulars determined by different parts coupledtogether in the installation. Injection fluids circulate through thesevertical passages:

C1—It is placed in the Middle Plug (17). They are passages in the FreeMandrel Assembly (C) central body.C2—The Annular (e6) where the regulated pressure (#) is dischargedthrough the Upper Formation Injection Valve (18) and conducted to theAnnular (e9) placed between the Telescopic Union inner body (37) and theinterior of the Fixed Bottom Hole Assembly (D). C2 are eccentricvertical passages in the FBHA (D) which connect (e6) with (e9).C3—Vertical passage containing Valve (36)C4 Shear Out inner passage

Note: Annular space or Annular is the space between the inner diameterof an exterior tube and the larger diameter of an interior tube. Bothtubes can or cannot be concentric. There are several Annulars in thisinvention layout:

e1 Between the Casing (10) and the 73.026 mm (2″⅞) Tubing (9)e2 Between the Casing (10) and the FBHA (D)e3 Between the Casing (10) and the Injector Plug (41)e4 Between the Casing (10) and the 60.325 mm (2″⅜) Tubing (47)e5 Between the Casing (10) and the Shear Out (48)e6 Between the Middle Plug (17) and the FBHA (D)e7 Between the Upper Mandrel Jacket (15) and the Upper Injection Valve(18)e8 Between the Lower Valve (21) and the FBHA (D) interiore9 Between the Telescopic Union inner body (37) and the inside of theFBHA (D)e10 Between the Telescopic Union outer body (39) and the On Off (43)e11 Between the Injection Tube (40) and the Injector Plug (41)

As all components and their characteristics have been defined, herefollows their layout and existing relationships among them.

According to FIG. 1, the equipment is composed of A, B, C, D, and EAssemblies. In this Figure, transverse cross-sectional lines areindicated (I-VIII) to facilitate the comprehension of the structures ofsaid assemblies. Only some components are indicated to facilitate thecomprehension of the invention structure:

9—73.026 mm (2″⅞) Tubingi—Tubing (9) Interior. (Direct)

10—Casing

37—Telescopic Union inner body

38—Telescopic Union Seal Rings

39—Telescopic Union outer body

40—Injection Tube 41—Injector Plug

42—Rupture Disc passage

43—On Off 44—Upper Packer 46—Lower Packer

47—60.325 mm (2″⅜) Tubing

48—Shear Out 49—Upper Formation Casing Perforations 50—Lower FormationCasing Perforations

FIG. 2 corresponds to Surface Assembly (A) made up of:

1—Pipeline from Water Power Plant

2—Catcher 3—Lubricator 4—Mast 5—Impeller 6 ₁—V1 (Standard Valve) 6 ₂—V2(Standard Valve) 6 ₃—V3 (Standard Valve) 6 ₄—V4 (Standard Valve)

6 ₅—73.026 mm (2″⅞) conventional full passage Injection Valve

7—Retention Valve 8—Well Head

9—73.026 mm (2″⅞) Tubing

I—Tubing Interior (9) (Direct)

e1—Annular between 9 and 10

10—Casing

FIG. 3 corresponds to Transport Assembly (B) made up of:

11—Fishing Neck 12—Retention Valve 13—Rubber Cups 14—Lower Connector

In this Figure the injection fluid provided from the Plant isrepresented by the (+) symbol which crosses it all over.

FIG. 4 corresponds to the Free Mandrel Assembly (C) made up of:

15—Outer Jacket 16—Seal Ring 17—Middle Plug 18—Upper Formation InjectionValve

19—Middle Plug radial passage

20—Seal Ring 21—Lower Formation Injection Valve 22—Lower Plug 23—SealRing

Incoming injection fluid is represented here with the (+) symbol.

It is divided into two streams:

1—It enters through the upper part of the Injection Regulating UpperValve (18) which delivers the already controlled fluid (#) to beinjected in the upper formation through the Middle Plug (17) radialpassage (19).2—It circulates through the Annular (e7) to guide the fluid through theMiddle Plug (17) vertical passages (C1) (not shown in this view) andfeed with injection fluid (+) the Lower Injection Valve (21) whichdelivers the controlled fluid (*) to inject in the Lower Formationthrough the Lower Plug (22).

In FIG. 5, the fluid (+) goes through the Transport Assembly (B) and theFree Mandrel Assembly (C) and enters the injection fluid inlet (+) inits upper part. The controlled fluid (#) continues towards the UpperFormation by the lower part of the Upper Injection Valve (18) and comesout through the Middle Plug passage (19). Injection Fluid (+) continuesthrough the vertical passages, not shown in this view, until it feedsthe Lower Injection Valve (21) in its upper part and, from here, thecontrolled fluid (*) comes out to inject the Lower Formation through theLower Plug (22).

FIG. 6 represents the Fixed Bottom Hole Assembly (D) made up of:

24—Upper Body 25—Upper Packer Collar 26—Seal Ring 27—Lock Nut 28—LowerBody 29—Seal Ring 30—Spacer

31—Spacer Injection outlet Perforation

32—Lower Packer Collar 33—Seal Ring 34—Seat 35—Seal Ring 36—CasingProtective Valve 10—Casing (10)

e2—AnnularC2—Vertical passageC3—Vertical passage

In FIGS. 7A and 7B, injection fluid (+) enters through 73.026 mm (2″⅞)(9) (i) Tubing into the Assembly (B) upper end, goes through theTransport Assembly (B), then goes into the Free Mandrel Assembly (C)through the upper end of the Upper Injection Valve (18) and comes outalready controlled (#) towards the Upper Formation going through theAnnular (e6) and the Spacer Injection outlet Perforation (31). Then itgoes through vertical passages (C2) of the FBHA (D) and the Annular(e9). Simultaneously, the other injection fluid stream (+) coming intothe Upper Mandrel flows through the Annular (e7), the vertical passagesof the Middle Plug (C1), (only shown in FIG. 7B) until it reaches theupper end of the Lower Injection Valve (21), which controls the fluid tobe injected in the Lower Formation (*). Said injection fluid (+) streamgoes through the Lower Plug (22) and continues through the TelescopicUnion (37).

FIG. 8 corresponds to the B, C, D and E Assemblies. In addition to thealready defined components and so as not to fall into repetitions, theseare the remaining ones:

37—Telescopic Union inner body39—Telescopic Union outer body

40—Injection Tube 41—Injector Plug

42—Rupture Disc passage

43—On-Off 44—Upper Packer

In this Figure, the injector circuits of both formations arerepresented. The injection fluid (+) enters through 73.026 mm (2″⅞)Tubing (9) (i), goes through the Transport Assembly (B), gets into theFree Mandrel Assembly (C) through the upper end of the Upper InjectionValve and comes out as controlled fluid (#) towards the Upper Formationthrough the Middle Plug radial passage (19). It passes through theAnnular (e6) and the Spacer Injection outlet Perforation (31). Then itchannels through the FBHA (D) vertical passages (C2), the Annulars (e9),(e10) and (ell), and the Rupture Disc passage (42).

Simultaneously, the other injection fluid stream (+) that goes into theUpper Mandrel, flows through the Annular (e7), the Middle Plug (17)vertical passages (C1) until it reaches the upper end of the LowerInjector Valve (21) which controls the fluid to be injected in the LowerFormation. (*). It goes through the Lower Plug (22) and continuesthrough the inside of the Telescopic Union (37 and 39), the InjectionTube (40) and the Injector Plug (41). Meanwhile the Annular (e1), (e2)and the vertical passage (C3) are kept without pressure (white space).

In FIGS. 9, 11 and 13, the invention components that have not beenmentioned follow below.

46—Lower Packer

47—60.325 mm (2″⅜) Tubing

48—Shear Out

49—Casing Upper Perforations—Upper formation50—Casing Lower Perforations—Lower formation

In FIG. 9, it can be observed that there is no pressure in the Annulars(e1), (e2) and in the passage (C3) (white space). The Upper FormationInjection is the only one represented, that is, the Upper InjectionValve (18) is regulating the flow (#) and the lower one (21) is blocked.So, the lower valve (21) is represented as if it were a solid body thatblocks fluid passage. For that reason, the central passage(corresponding to the Lower Formation circuit) is shown without pressureor fluid (white space). Consequently, the Injection Plant pressure (+)acts through 73.026 mm (2″⅞) Tubing (9) (i), as the regulated fluid (#)is injected to the Upper Formation through the Casin Upper Perforations(49). Through the Annular (e1), (e2) and the passage (C3) there is nofluid circulation. There is only hydrostatic pressure (white space).

In FIG. 10, a transverse cross-sectional view on line (FIG. 1), theAnnulars (e2) are marked as empty (white space). The Plant injectionfluid circulation (+) goes through the Middle Plug (17) verticalpassages (C1) and comes out regulated (#) through the Middle Plug (17)transversal (radial) passage (19) to the Annular (e6) and through thevertical passages (C2) (#).

In FIG. 11, it can be observed that in the Annulars (e1),(e2) and thepassage (C3) there is no pressure (white space) as only the LowerInjection Formation is represented. The injection fluid (+) that entersthrough 73.026 mm (2″⅞) (9) (i) goes through the Transport Assembly (B)and comes into the Free Mandrel Assembly (C) through the upper end ofthe blind Upper Injection Valve (it does not allow fluid passage and itis represented as a solid). The Annular (e6), Spacer Injection outletPerforation, the FBHA (D) vertical passages (C2), the Annulars (e9),(e10) and (e11) and the Rupture Disc passage (42) have no pressure. Nofluid circulation is observed in the figure.

At the same time, the other injection fluid stream (+) coming into theUpper Mandrel flows through the Annular (e7) and the Middle Plugvertical passages (C1) until it reaches the upper end of the LowerInjector Valve (21), which controls the fluid to be injected in theLower Formation (*). Said injection fluid stream (*) goes through theLower Plug (22) and continues through the interior of the TelescopicUnion (37 and 39), Injection Tube (40), Injector Plug (41), 60.325 (2″⅜)(47) Tubings, Lower Packer (46), the 60.325 mm (2″⅜) (47) and Shear Out(48).

Meanwhile, the Annulars (e1) and (e2), and the vertical passages (C2)and (C3) are kept without pressure (white space).

FIG. 12, a transverse cross-sectional view on line IV-IV (FIG. 1), showsthe controlled fluid (*) circulation to be injected in the LowerFormation through the Lower Plug (22) central passages. Meanwhile theAnnular (e2) and the vertical passages (C2) and (C3) are kept withoutpressure (white space).

FIG. 13 shows that in the Annulars (e1) and (e2), and passage (C3) thereis no pressure as simultaneous Injection in the Upper (#) and Lower (*)Formations with regulated fluids are represented here. Valves (18) and(21) are regulating injection fluids in both formations. Consequently,the injection fluid (+) enters the 73.026 mm (2″⅞) Tubing (9) (i), goesthrough the Transport Assembly (B) and flows into the Free MandrelAssembly (C) through the Injection Valve upper end (18) to the upperformation (#) and in the lower one (*), going out through perforations(49) and (50). To complete the regulated fluid circuit to be injected inthe Upper Formation as shown in FIG. 9, this fluid course is added as itcomes out of the Rupture Disc passage (42) until it gets into thechamber delimited as follows:

1. In the upper part by the lower side of the Upper Packer (44)2. In the outer part by the Casing (10)3. In the inner part by the Telescopic Union (37 and 39), Injection Tube(40) and Injector Plug (41)4. In the lower part by the upper side of the Lower Packer (46)

That is to say, the regulated fluid (#) is forced to go through theCasing Upper Perforations (49) and enter the Upper Formation.

To complete the regulated fluid circuit to be injected in the LowerFormation (*) as shown in FIG. 11, this fluid course is added as itcomes out of the Injector Plug central passage (41), 60.325 mm (2″⅜)Tubings (47), Lower Packer (46), 60.325 mm (2″⅜) Tubings (47), and ShearOut (48), until it gets into the chamber delimited as follows:

1. On the upper part by the lower side of the Lower Packer (46)2. On the outer part by the Casing (10)3. In the inner part by the 60.325 mm (2″⅜) Tubings and the Shear Out(48)4. On the lower part by the bottom hole

That is to say, the regulated fluid (*) is forced to go through theCasing Lower Perforations (50) and enter the Lower Formation.

FIG. 14, a transverse cross-sectional view on line V-V (FIG. 1), showsthat there is no fluid circulation through the Annular (e2) and thewhite (C3) passage, that is to say, no fluid circulation is observedwithin them. Through the interior of the Telescopic Union (37) innerbody, the controlled fluid (*) is conducted to the Lower Formation (*),and the controlled fluid (#) for the Upper Formation is conductedthrough the Annular (e9).

FIG. 15, a transverse cross-sectional view on line VI-VI (FIG. 1),represents the Lower Formation injection fluid (*) circulation throughthe Injection Tube (40) central passage and the Upper Formationcontrolled fluid (#) through the Annular (e9) while there is nocirculation through the Annular (e2).

FIG. 16, a transverse cross-sectional view on line VII-VII (FIG. 1),represents the Upper Formation fluid injection (#) that comes throughthe Annular (e11), goes through the Rupture Disc passage (42), fills theAnnular (e3) and goes through the Casing Upper Perforations (49) untilit gets to the Upper Formation. The Lower Formation injection fluid (*)goes through the Injection Tube (40) interior.

FIG. 17, a transverse cross-sectional view on line VIII-VIII (FIG. 1),shows injection fluid (*) flowing to the Lower Formation through theShear Out (48) central passage (C4) and the Annular (e5), coming outthrough Casing Lower Perforations (50) until it (*) reaches the LowerFormation.

FIG. 18 represents the recovery chamber where it can be seen how lowpressure fluid (x) is injected through the annular to recover el TA (B)and the FMA (C). Their upstroke is shown. Fluid (x) with the necessarypressure to perform the TA and FMA upstroke has too be injected throughthe annular (e1). This fluid enters through the Casing Protective Valve(36). This makes the TA (B) and the FMA (C) move to the surface wherethey will finally insert into the Catcher (2). Fluid (---) with apressure slightly lower than injection pressure flows over theseassemblies. Low pressure (x) pressurizes both formations. Thisparticularity has already been mentioned as a technical operationaladvantage of the invention. It is advantageous because the formationsare never depressurized.

FIG. 19, a transverse cross-sectional view on line I-I (FIG. 1), showshow Injection Fluid (+) coming from the Water Plant (not shown here) isinjected through 73.026 mm (2″⅞) Tubing (9) Interior (i) (Direct),whereas the annular (e1) between the 73.026 mm (2″⅞) Tubing (9) and theCasing (10) shows no fluid circulation.

FIG. 20, a transverse cross-sectional view on line II-II (FIG. 1), showsthat the dislodged fluid (---) returns through Tubing 9 (i) (Direct) dueto the FMA (C) upstroke. Low pressure fluid (x) is injected through theannular (e1) between (9) and (10) when the FMA (C) upstroke is required.

DETAILED DESCRIPTION OF THE INVENTION

According to the scheme represented in FIG. 1 of the Free MandrelSystem, Protected Casing, the invention layout is composed of:

A—Surface Assembly (SA) B—Transport Assembly (TA) C—Free MandrelAssembly (FMA) D—Fixed Bottom Hole Assembly (FBHA) E—ComplementaryAssembly (CA) 1—(A)—Surface Assembly (SA)

It is schematically represented in FIG. 2. It is the assembly ofconventional parts such as valves (6 ₁), (6 ₂), (6 ₃), (6 ₄), (7) and(8) properly laid out to perform the required operation of the FreeMandrel System, Protected Casing, with additional parts speciallydesigned to complement this operation. These parts are the Lubricator(3) with the Catcher (2), the Mast (4) to release and recover the FreeMandrel (C) and the Transport (B) Assemblies together by using the Mast(4) and the Impeller (5) to make the system work. The SA is screwed overthe Well Head (8) in the 73.026 mm (2″⅞) Full Passage ConventionalInjection Valve (6 ₅). The Lubricator (3) with the Mast (4) and theCatcher (2) in its lower end is screwed on Valve (6 ₅). Injection Fluidcomes from the Pipeline (1) into the well through Valve (6 ₁). When thisValve is open, the well can inject simultaneously in all Formations.When it is shut, it does not allow the injection fluid flow and the welldoes not operate. (Stand-By stage).

The Pipeline (1) diverges into a second branch and Valve (6 ₂) is shutduring that operation. When it is open, it allows the injection fluid toflow to the Impeller (5). This injects at low pressure in the Annular(e1) to perform the FMA (C) upstroke which is required to recover allinstalled Injection Valves.

This procedure is used to drive the Impeller (5) Circulation Pump, whichuses this fluid as driving power.

The Valve (6 ₃), placed at the upper end of the Lubricator (3) is keptclosed during the injection. It is only opened to retrieve the FMA (C)(upstroke).

The Impeller (5) allows the injection fluid to circulate from the Casing(10) to the 73.026 (2″⅞) Tubing (9) (i), through the Casing ProtectiveValve (36) for the FMA (C) upstroke to the surface.

It is clarified that the Impeller is a low pressure pump, with nomovable parts. It uses the Plant fluid as power fluid and injects it inthe Annular (e1) with the fluid it sucks from 73.026 (2″⅞) Tubing (9)(i).

This operation enables low pressure circulation to drive the TransportAssembly (B) and the Free Mandrel Assembly (C) in their upstroke fromthe FBHA (D) until it is trapped in the Catcher (2).

The Valve (6 ₁) is kept open for the downstroke whereas Valves (6 ₂), (6₃) and (6 ₄) are kept shut. The injection fluid push and the FMA (C)weight will insert the FMA (C) into the FBHA (D) while automaticallybeginning the selective injection in the Formations.

For this operation, a flow, not larger than 400 m³/a day, is recommendedto go through Valve (6 ₁) to prevent the FMA (C) from inserting into theFBHA (D) with excessive impact. In most downstrokes, the Operator opensValve (6 ₁). Then, he can leave the location as the operation iscompletely automatic.

Only in injected flows over 400 m³/a day, it is necessary for theOperator to liberate the flow completely after 30 minutes to leave thewell in ideal operating conditions.

The above-mentioned Surface Assembly (A) is screwed to the Well Head(8). Its hydraulic circuit consists of conventional valves and theImpeller with a feeding line coming from the Water Plant.

The Pipeline separates into two branches. The first one goes into the SA(A) central passage through a first Valve (6 ₁) and the second branchconnects with the Impeller (5) through a second Valve (6 ₂). TheImpeller connects to the Annular (e1) through the Well Head (8).

The third Valve (6 ₃) is placed at the Lubricator (3) outlet and isclosed while operating. When it is open, it allows the 73.026 (2″⅞)Tubing (9) (i) fluid to re-circulate to the Annular (e1) for the FMA (C)upstroke.

The 73.026 mm (2″⅞) Full Passage Injection Valve (6 ₅), connected to theWell Head (8), allows the FMA (C) to run in both strokes and theinjection and return fluids flow to retrieve the FMA (C).

The Valve (6 ₄) is used to recover the FMA (C) without the Impeller (5)assistance or when it does not work properly. This process works byopening Valve (6 ₂) to let a small volume of injection fluid flow,keeping the Annular (e1) pressure below 5 kg/cm², and making the fluidcirculate through Valve (6 ₄). A tank truck is used to collect the fluidcoming from the FMA (C).

As a reference, it can be stated that for the mentioned depth, that is,2,500 m, the fluid volume is approximately 7500 liters.

2—(B)—TRANSPORT ASSEMBLY—TA

It is schematically represented in FIG. 3. It is one of the dynamiccomponents that moves with the Free Mandrel Assembly (C) from theSurface Assembly (A) to its insertion in the Fixed Bottom Hole Assembly(D) during the FMA (C) downstroke or vice versa, upstroke. It consistsof a Lower Connector (14), a Retention Valve (12) for the upstroke,Rubber Cups (13) and the Fishing Neck (11) screwed together. TheTransport Assembly (B) is used to transport the Free Mandrel Assembly(C).

Obviously, said Assembly (B) is specially designed according to theoperating requirements of the invention device.

It is essential in the FMA (C) upstroke as the Rubber Cups (13) expandagainst the 73.026 mm (2″⅞) Tubing (9) taking the utmost advantage ofits volume when they receive the upward injection fluid push. This pushalso closes the Retention Valve (12) for the greatest fluid efficiency.

FIG. 5 shows the Transport Assembly (B) screwed to the Free MandrelAssembly (C) upper end.

The TA ends in its upper extreme in a normalized Fishing Neck (11),according to API (American Petroleum Institute) specifications, whichallows it to be trapped by the Catcher (2) (FIG. 2) at the end of theupstroke and detached from it at the downstroke start.

In case of any inconvenience, TA (B) and FMA (C) can be trapped by meansof Slickeline equipment.

The TA (B) ends in its lower extreme in the Lower Connector where it isscrewed to the Free Mandrel Assembly (C).

The assembly of (B) and (C) is schematically represented in FIG. 5.

3 (C)—Free Mandrel Assembly—FMA:

It is schematically represented in FIG. 4. It is the main dynamiccomponent that travels from SA (A), in its downstroke, and is insertedinto the FBHA (D) to begin selective injection in different Formations.

In its upstroke, it moves injector valves to be examined or removed.

It is one of the five Assemblies composed of totally new parts. It hasbeen graphically represented in FIGS. 4, 5, 7A, 7B, 8, 9, 11, 13 and 18.

It has been specially designed for the operation of the system appliedto selective injection in different Formations. As it has beenabove-mentioned, it can be applied to several formations but in thisspecific explanation, it has been reduced to only two formations tofacilitate the explanation.

Every Mandrel contains an Injection Valve in its interior, except theLower one which is only integrated by an Injection Valve speciallydesigned for this purpose.

In FIG. 4, a Free Mandrel Assembly to inject in two formations isschematically represented.

The difference between the Upper Mandrel which contains an UpperFormation Injection Valve (18) in its interior and the Lower Mandrelcomposed only by a Lower Formation Injection Valve (21) speciallydesigned, can be observed in FIG. 4.

The Upper Free Mandrel is screwed at its upper end to the TransportAssembly (B) by the Outer Jacket (15). This closes with the FBHA (D)Upper Packer Collar (25) through the Seal Ring (16). It contains theUpper Formation Injector Valve (18) in its interior. It is screwed tothe Middle Plug (17) in its lower end.

The Middle Plug (17) closes with the FBHA (D) Lower Packer Collar (32)with Seal Ring (20).

The Injection Valve (21) is screwed to the Middle Plug (17) lower end.This valve corresponds to the Lower Formation which ends in the LowerPlug (22). It closes with Seal Rings (23) in the Seat (34) in FIG. 6 ofthe Fixed Bottom Hole Assembly (D).

FIG. 4 shows the incoming fluid (+) which comes out regulated (#) fromthe Upper Formation Injection Valve lower end to fulfill the upperformation required conditions. Whereas, the incoming fluid (+) movesthrough the annular (e7) limited on the outside by the Upper MandrelJacket (15), goes through the Middle Plug (17) passages (C1) (not shownin this Figure), reaches the Lower Mandrel and is admitted by the LowerFormation Injection Valve (21) which transforms the fluid into (*).

As it has been previously described, the Upper Mandrel, which containsthe Upper Formation Injection Valve (18), receives the Plant fluid (+)and the regulated fluid for upper formation (#) required conditionsfinally comes out from the Upper Injection Valve lower end.

The incoming fluid (+) moves through the annular (e7) limited on theoutside by the Upper Mandrel Jacket (15) and on the inside by the UpperFormation Injection Valve (18). This (+) fluid reaches the Lower Mandrelthrough the Middle Plug (17) passages (C1) (not shown in FIG. 4) and isadmitted by the Lower Formation Injection Valve (21). That is to say,the Lower Formation Injection Valve (21) receives the incoming fluid (+)and transforms it into the fluid with the necessary conditions to beinjected in the Lower Formation (*).

4—(D)—Fixed Bottom Hole Assembly—FBHA:

It is schematically represented in FIG. 6. This Assembly is static. TheWorkover Equipment installs it with its lower end screwed to the On Off(43) upper end, and its upper end to the first 73.026 (2″⅞) Tubing (9)(i) lower screw of the string that communicates it with the Well Head(8).

The FBHA (D) lodges the FMA (C) so that hydraulic circuits arecompleted. They allow the Upper Packer (44) and the Lower Packer (46) tobe fixed from the surface without having to resort to Slickelineequipment or similar ones. Then Selective Injection is performed inevery Formation.

The FMA (C) seals the Upper Packer Collar (25) with Seal Ring (16) (FIG.4-6) and separates the injection fluid (+) contained in the 73.026 mm(2″⅞) Tubing (9) (i) that enters the Upper Mandrel through the TransportAssembly (B).

The Upper Free Mandrel is provided with a Middle Plug (17) in its lowerend. (FIG. 4). This Middle Plug seals the Lower Packer Collar (32) withSeal Ring (20) (FIG. 4-6) and prevents the fluid regulated by the UpperFormation Injection Valve from passing to the FBHA (D) lower chamber.

The Lower Formation Injector Valve (21) receives Injection fluid (+)through the Middle Plug (17) vertical passages (C1), regulates the flowthat is required for the Lower Formation Injection, and channels itthrough the Lower Plug (22) (FIG. 4) and to the Injection Tube (40)through the Telescopic Union (37).

The Casing (10) Protective Valve (36) is located in this lower chamber.It allows fluid passage to go through the Annular (e1) to 73.026 (2″⅞)Tubing (9) (i) Interior (Direct) but prevents the fluid from passingfrom the 73.026 mm (2″⅞) Tubing to the Annular (e1). This keeps theCasing (10) totally isolated from injection fluid pressure and contact.

In the upstroke, it impulses the Free Mandrel Assembly (C) to removeinjection valves.

FIGS. 7 A and B represent the TA (C) assembled with the FMA (C) insertedin the FBHA (D) in operating position, that is to say, ready to injectselectively in both Formations.

5—(E)—Complementary Assembly—CA:

It has been schematically represented in FIG. 8 where it is screwed inthe lower part of the FBHA (D).

It is composed of specific parts that correspond to the inventionequipment design. They are complemented by other parts of common use inPetroleum Industry.

On the outside, the lower part of the FBHA (D) screws in the upper partof the On Off (43) which, in its lower part screws in the Upper Packerupper end (44). (Both are common use parts). The Injector Plug (41)screws in the Upper Packer lower part. This Plug lodges the passagewhere the Rupture Disc is located (42). Both are specific parts of thisequipment. This Rupture Disc is used to fix the Upper Packer (44) and,once it has been fixed, the pressure is raised until it bursts andenables the circuit to perform Upper Formation Injection.

The Telescopic Union Inner Body (37) is screwed to the FBHA (D)internally and in a concentric pattern. It slides and seals inside theTelescopic Union Outer Body (39).

The Telescopic Union has two functions:

I) When the Upper Packer (44) fixes, there is a longitudinaldisplacement that is absorbed by the Telescopic Union.II) It allows On Off (43) rotation and longitudinal displacement toremove the FBHA (D) with the tubing string.

The Injection Tube (40) is screwed in the lower part of the TelescopicUnion Outer Body (39) and is screwed in the Injector Plug (41) in itslower end.

The 60.325 mm (2″⅜) (47) Tubings that connect the Injector Plug (41)with the Lower Packer (46) are schematically represented in FIG. 9. Therequired quantity of 60.325 mm (2″⅜) (47) to separate both packers arescrewed in the lower part of the Injector Plug (41) and the Lower Packer(46), in its upper part.

Other sections of 60.325 mm (2″⅜) (47) Tubings connect the Lower Packer(46) with the Shear Out (48).

The 60.325 mm (2″⅜) (47) Tubing is screwed in the lower part of theLower Packer (46) and, at the other end, in the upper part of the ShearOut (48) which is also used to fix the Lower Packer (46). This circuitis closed by the Shear Out (48) interior ball. This allows a pressureincrease in the 60.325 mm (2″⅜) Tubing (47). Once the Lower Packer (46)is fixed, pressure continuous being increased until the Shear Out (48)ball is displaced. This enables the circuit to perform the LowerFormation Injection.

6—Assembly Sequence for the Invention Equipment Installation

The assembly sequence at the well head is the following:

I) The Shear Out (48) (FIG. 9) is assembled, ball included, in the60.325 mm (2″⅜) (47) tubings.II) The 60.325 mm (2″⅜) (47) Tubing is screwed with the Lower Packer(46).III) The 60.325 mm (2″⅜) Tubings (47) required for the separationbetween the Formations to be injected are screwed to the upper end ofthe Lower Packer.IV) The Injector Plug (41) (FIG. 8) is screwed to the last 60.325 mm(2″⅜) Tubing (47). The FBHA (D), screwed to the CA (E) (FIG. 8), isdelivered already assembled, including the Rupture Disc and the propertorque so that the Workover Equipment screws the Injector Plug (41) onthe 60.325 mm (2″⅜) Tubing upper end (47), required by the well tocomprise the distance of the Upper Formation Perforations (49).V) The required quantity of 73.026 mm (2″⅞) Tubings (9) to reach thesurface and screw in the Full Passage Conventional Injection Valve isassembled to the FBHA (D) upper end.VI) The Lubricator (3) will be installed on the 73.026 mm (2″⅞) TubingFull Passage Conventional Injection Valve (65).VII) The Mast (4) can be left assembled in the Lubricator or will beplaced whenever a change of the Free Mandrel Assembly (C) is necessary.

The rest of the SA (A) is assembled as indicated in FIG. 2.

7—Description of the Equipment Operation

Once the different components of the invention embodiment have beendetermined and developed to explain their nature, the description isherein complemented with a summary of what has already been describedabout the functional and operative relationship of its parts and theoutcome they provide.

Installation:

According to the previous paragraphs and, in other words, for theoperational description of the invention device, the following are theoperations needed for its installation in a specific well:

1::1 Complete Verification of the Tubing String Water Tightness

As the complete Tubing string is assembled, water tightness tests areperformed using the Full Blind Plug Not illustrated.

Once the 73.026 mm (2″⅞) Tubing (9) (i) has been assembled up tosurface, its water tightness is tested. The Well Head pressure isincreased up to 3000 psi; the valve is closed and, for 20 minutes, it isnecessary to verify that it keeps constant.

Once tubing water tightness testing has been satisfactory, the FullBlind Plug is removed.

1::2 Lower Packer (46) Fixing

The FMA (C) is lowered with the Blind Middle Plug, that is to say, thefluid pumped by the Workover Equipment is only injected through theLower Mandrel. It pressurizes the Telescopic Union (37 and 39), theInjection Tube (40), the 60.325 mm (2″⅜) Tubings (47) and the Shear Out(48). (This circuit is closed). As the pressure is slowly increased, theLower Packer (46) is fixed by cutting the pins. This is perceived by theimpact of Jaws against the Casing (10). The proper fixing is verifiedaccording to the Packer supplier specifications.

After that, the pressure is increased until the Shear Out (48) ballenables the Lower Formation Injection. Meanwhile, Formation admissiontests are made according to the established program. Pressures andvolumes are also checked. During this operation, the pressure in thecircuit to fix the Upper Packer (44) is null (white space).

1::3 Upper Packer (44) Fixing

The FMA (C) is removed with the Blind Middle Plug, and the Middle Plug(17) is placed. The Lower Plug is changed by a Blind Lower Plug. In thiscase, when the fluid is pumped through the 73.026 mm (2″⅞) Tubing (9),it is all directed to the Upper Formation Injection Circuit. This isblocked in the Injector Plug (41) by the Rupture Disc (42).

When pressure is increased by the Workover Equipment Pump, the requiredpressure is reached by the rupture of the Upper Packer (44) pins and theUpper Packer is fixed. Its proper position is checked according to whathas been recommended by the manufacturer. Thereon, the pressurecontinues to be increased until the Rupture Disc bursts and this enablesthe circuit to inject in the Upper Formation.

Admission tests are performed at different pressures according to thedefined program.

1::4 Downstroke or FMA (C) insertion

Open Valves (6 ₁) and (6 ₅). Keep all the other valves closed. The FMA(C) is normally assembled for simultaneous injection with the MiddlePlug (17), the Lower Plug (22) and corresponding regulated InjectionValves according to the injection program. The Formation SelectiveInjection begins automatically when the FMA (C) arrives and inserts intothe FBHA (D).

After assembling the Well Head (8), the FMA (C) can be installed withthe Workover Equipment Pump or with the Plant Injection Fluid.

During the downstroke, fluid is injected in both formations without anytype of control. In both cases, the fluid pushes the FMA (C) with theUpper and Lower Formation Injector Valves regulated according to thewell Injection program until the FMA (C) inserts into the FBHA (D). Atthis moment, Selective Injection is automatically started in bothformations according to what has been programmed. Once the downstrokehas begun, the Operator does not need to wait for the FMA (C) to reachand insert into the FBHA (D) as it will be done in 20 or 25 minutes andSelective Injection will begin automatically.

1::5 Upstroke to recover the FMA (C) on the surface

Close (6 ₁) Valve (FIG. 2) and partially open Valve (6 ₂) and completelyopen Valve (6 ₃). This allows Injection Fluid to flow into the Impeller(5). This component drives it through the Annular (e1), opens the CasingProtective Valve (36), goes into the FBHA (D) lower chamber and drivesthe FMA (C) to the surface until it is hooked in the Catcher (2). Thewell is depressurized. The FMA (C) together with the TA (B) are removedby turning round the Catcher (2) and then, they are hoisted by the Mast(4).

If the well is not depressurized, the Catcher (2) can not be turnedround. For safety reasons, it is designed to block itself, even if thereis low pressure. In this case, the Operator can leave and perform otheractivities. When the operator comes back, he will find the FMA (C) inthe Catcher (2) and the Formations already pressurized.

At the Well Head, the following components can be replaced:

-   -   a) The Injector Valves by removing the used ones and placing new        controlled units.    -   b) The FMA (C) with the valves already installed.

In both cases the task will be performed by the operator. Obviously, FMA(C) replacement is faster with the valves already controlled.

1::6 Selective Injection Operation in Both Formations

The Injection Fluid (+) reaches the Surface Assembly (A) along aPipeline (1) fed from the Water Plant and enters the System through (6₁) Valve completely open. Valves (6 ₂), (6 ₃) and (6 ₄), shown in FIGS.1 and 2, must be closed.

The 73.026 mm (2″⅞) Injection full passage Conventional Valve (6 ₅) hasto be open to allow the FMA (C) to get through. The injection fluid,which enters the well through Valve (6 ₁), fills the Lubricator (3) (+)(FIG. 2) and the fluid flows through 73.026 (2″⅞) Tubing (9) (i) (+),goes through the TA (B) (+) and enters the Upper Mandrel (+).

In the Upper Mandrel, the Upper Formation Injection Valve (18) (FIGS. 4,5, 7A, 7B, 8 and 9) takes the (+) fluid and regulates the flow (#) thatmust be injected in that Formation by guiding it through the Middle Plug(17) passage (19).

This regulated fluid (#) fills the chamber limited in the upper end bythe Seal Ring (16) that blocks the Upper Packer Collar (25). In thelower part, it is limited by the Seal Ring (20) with the Lower PackerCollar (32).

The already regulated fluid is compelled to go through the Annular (e6)to the FBHA (D) inner side passage (C2) (FIGS. 7A, 7B and 8) throughwhich it successively discharges into the Annulars (e9), (e10) and(e11). On the outside, they remain limited with the On Off (43) interiorand the Upper Packer (44). On the inside, it is limited by theTelescopic Union exterior (37 and 39) and the Injection Tube (40). Inthe lower end, the limit is the Injector Plug. (41). The fluid goes outthrough the Rupture Disc passages (42) (FIGS. 8 and 9).

The fluid, which is regulated (#) by the Upper Injector Valve (18) (FIG.4), is oriented through the Injector Plug (41) Rupture Disc passage (42)(FIGS. 8 and 9) to the chamber limited by:

I) The Upper Packer (44) lower side in the upper end (FIG. 9)II) The Well Casing (10) on the outside (FIG. 9)III) The Telescopic Union (37 and 39) and the Injector Tube (40) in theinside (FIG. 9)IV) The Lower Packer (46) upper side in the lower end (FIG. 9)

The Fluid (#) regulated by the Upper Formation Injection Valve (18)(FIG. 4) is then pushed to inject in the Upper Formation through theCasing Upper Perforations (49) (FIGS. 9 and 13).

This is the course taken by the regulated fluid to go into the UpperFormation (FIG. 16). The Injection fluid (+) takes up the UpperFormation Injection Valve outer chamber (e7) in the Upper Mandrel. Thefluid flows through the Middle Plug (17) vertical passages (C1) (FIGS.4, 7B, 8 and 9). These passages run into a chamber and the fluid (+) istaken by the upper part of the Lower Formation Injection Valve (21)(FIGS. 4, 7B and 11), which regulates the flow (*) to be injected in theLower Formation. This already regulated fluid (*) to be injected in theLower Formation is conducted through the Middle Plug inner part (22),Telescopic Union (37 and 39) inner part, Injection Tube (40), InjectorPlug inner part (41), 60.325 mm (2″⅜) Tubings (47) and Lower Packer(46), and finally unloaded through the Shear Out (48) (FIGS. 1, 9, 11and 13) into the chamber limited by:

I) Lower Packer (46) lower side in the Upper end (FIGS. 9, 11 and 13)II) The Well Casing (10) on the outside (FIGS. 9, 11 and 13)III) The bottom hole in the lower end

The Lower Formation regulated fluid (*) is introduced through the CasingLower Perforations (50) in the above-mentioned Formation (FIGS. 11, 13and 17).

This is the course taken by the regulated fluid (*) to go into the LowerFormation.

FIGS. 7A and 7B show two sections of the Transport Assembly (B) screwedin the upper end of the FMA (C) inserted into the FBHA (D) and injectingselectively in both formations. Both sections show the circuits thatdrive fluids to every formation. The Plant Fluid (+) is taken to beregulated by the Upper Formation Injection Valve (18) for the UpperFormation (#) and the Lower formation Fluid (*) is taken to be regulatedby the Lower Formation Injection Valve (21).

In FIG. 7A, section is parallel to the Middle Plug (17) InjectionPassage (19).

In FIG. 7B, section is perpendicular to the Middle Plug (17) Injectionpassage (19).

FIG. 4 shows the fluid that has been regulated for the Upper Formationrequired conditions.

According to the previous detailed explanations and in order toreinforce the invention operational comprehension, here follows asummary of the fluid operative paths. This fluid is injected through thecomponent parts of the invention structure in two formations: Upper andLower Formations in the simplified model adopted as an example toperform one of the possible applications of the invention.

Starting from the Surface Assembly (A), the symbol (+) is used torepresent the fluid provided by the Plant through the pipeline (1),Valve (6 ₁). The fluid already regulated by the Valve (18) and to beinjected in the Upper Formation is represented by (#) symbol. The fluidregulated by Valve (21) and to be injected in the Lower Formation isrepresented by the (*) symbol.

The fluid that comes from the Plant goes into the Tubing (9) (i) (+)through the 2″⅞ conventional full passage Injection Valve (6 ₅). To makethis operation possible, the Valve (6 ₁) must be open and the (6 ₂), (6₃), and (6 ₄) valves shut until the fluid reaches the Free MandrelAssembly (C) (FIG. 4) through the Transport Assembly (B) (FIG. 3).Selective Injection is then performed in the two formations (#) and (*).

In a downward description, it can be observed that two watertightchambers have been formed. They make it possible to direct the fluid tobe injected:

1—An upper chamber (FIGS. 7A, 7B, 8, 9, 11 and 13) limited by theclosure produced between the upper Seal Ring (16) that packs in theUpper Packer Collar (25), and the Plant pressure (+) contained in theTubing string up to this location.2—At the same time, an Upper Mandrel chamber will also be determined.This is contained between said closure produced by the upper Seal Ring(16) with the Upper Packer Collar (25) and the closure produced betweenthe Middle Plug (17) Seal Ring (20) with the Lower Packer Collar (32).This chamber contains the fluid to be injected (#) in the UpperFormation with pressure regulated by Injection Valve (18) and channeledthrough the Middle Plug (17) passage (19). Both the Plant pressure (+)in the annular (e7) and in the (C1) passage and the Injection Pressure(#) in the Upper formation coexist in this chamber (FIGS. 7A, 7B and 8).

The Free Mandrel Assembly (C) (FIG. 4) lodges the upper Injection Valve(18) that regulates the Upper Formation Injection (#) and is screwed inthe Middle Plug (17) in its lower part. The circuit that drives thisalready regulated fluid is identified by the symbol (#). It is driven(FIGS. 7A, 7B and 8) through the Middle Plug (17) passage (19), Annular(e6), FBHA (D) vertical passages (C2) to Annulars (e9), (e10) and (e11),Injector Plug (41) through Rupture Disc (42) passage to Annular limitedby:

I The Upper Packer lower part (44) (FIGS. 8, 9 and 13)II The Lower Packer upper part (46) (FIGS. 8, 9 and 13)III On the outside by the Casing (10) (FIGS. 8, 9 and 13)

The fluid to be injected goes through the Casing Perforations (49) andenters the Upper Formation.

3—The Lower chamber (FIG. 11) is determined by the closure of the LowerPacker Collar (32) and Middle Plug (17) Seal Ring (20) and Lower Plug(22) Seal Rings (23) with seat (34). The Lower Formation Injection Valve(21) admits the Plant Fluid (+) by its upper end and regulates it to beinjected (*) in the Lower formation according to the establishedconditions.

Between the Upper Mandrel Jacket (15) and the outside of the UpperRegulation valve (18), in the Annular (e7), the Plant (+) fluid feedsthe Lower Regulation Valve (21) through the Middle Plug (17) passages(C1). Said Valve (21) transforms the pressure and the volume asrequested for Lower Formation Injection.

FIGS. 7A, 7B and 8 show, in the FBHA (D), the circuit that drives thisregulated flow, identified by the symbol (*), to the Lower Formation. Itmust go through the Lower Plug (22), Telescopic Union (37 and 39),Injector Tube (40) through Injector Plug (41) central passage (FIGS. 8,11 and 13). In its end, the 60.325 mm (2″⅜) Tubings (47) are screwed.These tubings connect the Lower Plug (41) with the Lower Packer (46).The 60.325 mm (2″⅜) Tubings (47) and the Shear Out (48) are screwed tothe Lower Packer lower end; the fluid (*) flows through the Casing (10)Lower Formation Perforations (50) (FIGS. 1, 11, 13 and 17).

4—Free Mandrel Assembly Recovery Chamber (x) (FIG. 18) is the chamberlimited by the outside of the Injection Valve Jacket (21) and the FBHA(D) inner diameter, Annular (e8) (FIGS. 7A, 7B and 8). The chamber isclosed by the Casing Protective Valve (36). The fluid that fills it isat the pressure of the column that contains the Annular.

In order to make the Free Mandrel Assembly (C) return to the surface,low pressure fluid is injected (x) through the Annular (e1) and 73.026mm (2″⅞) Tubing 9 (Direct) is depressurized.

The Casing Protective Valve (36) opens and lets the fluid in. This fluiddrives the Free Mandrel Assembly (C) until it is caught in the Catcher(2). To remove the Free Mandrel Assembly (C) together with the TransportAssembly (B), it is only necessary to operate the Surface Valves in thefollowing way:

1—Close Valve (6 ₁). 2—Open Valve (6 ₂). 3—Open Valve (6 ₃).

4—Keep Valve (6 ₄) closed.

With this configuration, the Plant Water enters through the Impeller (5)into the annular. This opens the Casing Protecting Valves (36) allowingthe fluid to enter and produce the disconnection of the Free MandrelAssembly (C) and the Transport Assembly (B) from the FBHA (D). From thismoment on, the fluid produces the upward push that makes the Rubber Cups(13) expand and closes the Transport Assembly Valve (12) located in theFishing Neck (11).

The upward speed is proportional to the volume of the fluid injected inthe Annular (e1). The upstroke ends with the Free Mandrel Assembly (C)and the Transport Assembly (B) hooked together in the Catcher (2)located in the Lubricator (3).

To remove them from the well:

1) Turn the Catcher (2) eye-bolt until it adopts the “Catching”position. In this position, the Catcher cage retains the assemblies whenthey make an impact in their upstroke.

2) Close all Surface Assembly Valves (6 ₁,6 ₂,6 ₃,6 ₄).

3) Wait until 73.026 mm (2″⅞) Tubing (9) (Direct) pressure reaches zero.4) Turn the Catcher (2) 90° to remove it from the Lubricator (3).5) Raise the Free Mandrel Assembly (A) and the Transport Assembly (B)with the Mast (4).6) Lower the assemblies and unhook them for inspection or replacement.

To install the Free Mandrel Assembly (A) and the Transport Assembly (B),the reverse process has to be performed:

-   1) All surface Valves must be shut. (6 ₁ to 6 ₄).-   2) The two assemblies are hooked together, installed in the hoisting    system and then introduced in the Lubricator (3).-   3) The Catcher (2) is turned 90° to close the Lubricator (3).-   4) The Catcher eye-bolt is turned to the releasing position so that    the Free Mandrel Assembly (A) and the Transport Assembly (B) unhook    from the Catcher (2) and start the downward movement.-   5) Valve (6 ₁) is opened so that the fluid push makes the assemblies    descend at a proper speed, according to the injected flow.

A speed of about 70 to 85 meters/minute is considered reasonable for thedownstroke.

A greater downward speed is also possible. For example, 100meters/minute (shorter downstroke) and when it is close to the FBHA (D),slow down the speed to 50 meters/minute so that the insertion isadequate. Once the two assemblies are engaged, the pressure begins torise until it reaches the Pipeline pressure. In this moment, the systembegins to inject selectively in the two formations.

A manufacturing possibility, which leads to materializing thisinvention, and the way it works has been described. To complete thedocuments, here follows a synthesis of the invention contained in theclaims which come next.

(There appears a signature followed by a seal that reads “LUIS SALVADORCUNEO. Industrial Property Agent. Registration Number 1409”.)

1. A Free Mandrel system with annular protected from injection pressureconsisting essentially of five interconnected basic assemblies: aSurface Assembly including a mast for installation, a lubricator withcatcher to release and hook a mandrel assembly, the necessaryconventional valves and an impeller to enable its operation; a TransportAssembly comprising a fishing neck with a Retention Valve, a pair ofrubber cups that slide over a central tube and a lower connector whichenables it to connect with next said assembly; a Free Mandrel Assembly,a dynamic device consisting of said mandrel for every one of the wellexisting formations to be selectively injected with every said mandrellodging its corresponding injection valve and complemented with a FixedBottom Hole Assembly, a device screwed in the lower part of a 73.026 mm(2″⅞) tubing string and over an On Off, composed of a tubular bodylimited by an upper outer body, provided with means of connection withsaid Free Mandrel to complement hydraulic circuits they both contain, tocarry out said selective injection in every said formation and passthrough circulation vertical passages of an operative fluid, located indifferent planes at 90° between them, including at least, a casingprotective valve and also provided with means of coupling with aComplementary Assembly by its lower end to complete said necessaryhydraulic circuits for the operation of said system.
 2. A Free MandrelSystem with annular protected from injection pressure, as in claim 1,wherein said Surface Assembly, screwed to a well head, comprisingbesides said catcher, lubricator, mast, conventional valves hydrauliccircuit and impeller, a water plant pipeline with a first branchreaching said Surface Assembly central passage through a first valve,and a second branch connecting through a second valve with said impellerand well head, whereas said impeller feeds through said Retention Valve,a third valve and from said lubricator of said Surface Assembly where a73.026 m (2″⅞) conventional full passage injection valve is in its lowerend and connected to said well head including a fourth valve.
 3. A FreeMandrel System with annular protected from injection pressure, as in anyone of claims 1 and 2, wherein said Transport Assembly is a tubular bodyconsisting of said fishing neck in its upper end, said Retention Valvewith said pair of rubber cups in its middle part ending in said lowerconnector in its lower end, is prepared to transport said Free MandrelAssembly screwed to said connector.
 4. A Free Mandrel System withannular protected from injection pressure, as in any one of claims 1, 2and 3, wherein said Free Mandrel Assembly to perform said injection inupper and lower said formations, comprises an outer jacket with saidseal ring and injection valve for said upper formation screwed in thelower end in a middle plug which reaches a transverse passage throughsaid seal ring and injection valve for said lower formation screwed inthe lower end of said middle plug provided by a lower plug; said sealrings dose tightly with said Fixed Bottom Hole Assembly to complete saidtubular piece at its lower end.
 5. A Free Mandrel System with annularprotected from injection pressure, as in any one of claims 1, 2, 3 and4, wherein said Fixed Bottom Hole Assembly consisting of said upper bodyouter jacket provided with an upper packer collar, said seal ring and alock nut for said lower body with said seal ring, a spacer and injectionfluid outlet perforations to inject into said upper formation; saidlower packer collar with said seal ring, a seat and said seal rings;laterally, at least one said casing protective valve and said fluidvertical passages.
 6. A Free Mandrel System with annular protected frominjection pressure, as in any one of claims 1, 2, 3, 4, and 5, whereinsaid Complementary Assembly, screwed in the lower part of said FixedBottom Hole Assembly, comprises in its inner part a telescopic union, aninjector tube, an injector plug and a rupture disc passage; in its outerpart, said On Off screwed to the lower part of said Fixed Bottom HoleAssembly which, in its turn, is screwed to the upper part of said upperpacker On Off; said injector plug with said rupture disc passage isscrewed to said upper packer lower part and completing the installation,in said injector plug lower part, the necessary quantity of 60.325 mm(2″⅜) tubings to fix said lower packer in the right position to separateboth said formations, while at least one said 60.325 mm (2″⅜) tubing isplaced below said lower packer with a Shear Out at its end; saidperforations are disposed for said upper and lower formations.
 7. A FreeMandrel System with annular protected from injection pressure, as in anyone of the preceding claims, wherein said assembly connecting meansconsist of screws.
 8. A Free Mandrel System with annular protected frominjection pressure, as in any one of the preceding claims, wherein saidoperative fluid flowing through said hydraulic circuits of saidassemblies will be taken with the widest meaning of said fluid concept,comprising any kind of liquids or gases.
 9. A Free Mandrel System withannular protected from injection pressure, as in any one of thepreceding claims, wherein the number of said formations can be more thantwo.